to my surprise the two jardini are getting along just perfectly. The new addition to the tank is the smaller jardini, currently at 14". Also note that the smaller aro is much pinker and lighter in coloration.
The larger Jardini, for some reason isn't as aggressive. Very friendly. maybe it is because the owner of the tank is the lagest silver arowana who puts the others in check. The setup is 180 gallons, but planning to up grade sometime soon.